Muffler for internal combustion engines



May 3, 1955 c. JANEWAY MUFFLER FOR INTERNAL COMBUSTION ENGINES FiledMarch 9, 1954 Is Sheets-SL961. 1

I N VENTOR (DEA/ELL J/JNEH fiy ATTORNEY May 3, 1955 c. JANEWAY MUFFLERFOR INTERNAL COMBUSTION ENGINES 3 Sheets-Sheet 2 Filed March 9, 1954INVENIOR melvz'LL Jx'mzmey BY %44 V ATTORNEY May 3, 1955 C. JANEWAYMUFFLER FOR INTERNAL COMBUSTION ENGINES Filed March 9, 1954 3Sheets-Sheet 3 {bled 6L1. Jmsnay ATTORNEY United States MUFFLER FQRHNTERNAL CGMEUSTION ENGINES Cornell .l'aneway, Silver Spring, l'vid.

Application March 9, 1954, Serial No. 414,941

7 Claims. (Cl. Isl-56) This invention relates to mufflers for internalcombustion engines and the like.

Exhaust gases of an internal combustion engine leave said engine in astream having successive concentrations of said gases at relatively highpressures and intermediate concentrations of said gases at relativelylow pressures. The noise of the engine exhaust is due partially to thesaid gas impulses and partially to sound waves preceding the gas flow,said sound waves traveling through the exhaust gases as said gases passthrough the muffler. The structure of the mullier, and of itsembodiments, is based upon the simultaneous treatment of both theexhaust gases and the sound waves and may be effectively used for asingle cylinder or a multicylinder engine.

The muffler of this invention incorporates a combination of structuralcomponents which allows the exhaust gases to expand, cancels the soundwaves traveling through said exhaust gases by interference, and preventsback pressure restrictions. To diminish the sound waves, the exhaustgases having the sound waves traveling therethrough are divided into twostreams which are directed through two separate paths, one path beinglonger than the other by one half the wave length, or a multiplethereof, of the sound waves. Each of said streams is so directed throughthe mutller that the respective streams approaching each other fromopposite directions will meet at a portion of said muffler.

It is well known that the engine cycle used almost exclusively inautomobile engines is the four stroke cycle which requires four pistonstrokes or two crankshaft revolutions per cycle. In a one cylinderengine, there is one exhaust for every two revolutions of the crankshaftor for every 726 of rotation of the crankshaft. In a 2 cylinder engine,there is one exhaust for every revolution of the crankshaft or for every360 of rotation of the crankshaft. one exhaust for every one halfrevolution of the crankshaft or for every 180 of rotation of thecrankshaft. In a six cylinder engine there is one exhaust for every onethird revolution of the crankshaft or for every 120 of rotation of thecrankshaft. In an 8 cylinder engine there is one exhaust for every onequarter revolution of the crankshaft or for every 90 of rotation of thecrankshaft.

Because of the novel structure of the muffler, which includes, directlyadjacent to the exhaust inlet pipe, a forward expansion chamber having avolume equal to at least approximately ten times the displacement volumeof one cylinder, the muffler of this invention is capable of use bothwith a one cylinder engine or multicylinder engine to produce excellentsilencing effects.

An object of this invention is to provide a mufller which can beeffectively used for single cylinder and multicylinder internalcombustion engines.

Another object of this invention is to provide a muffler which allowseasy passage of the exhaust gases therethrou'gh.

A further object of this invention is to provide a In a 4 cylinderengine, there is muffler which allows for simultaneous expansion of theexhaust gases and attenuation of the sound by utilization ofinterference principle of sound waves.

A further object of this invention is to provide a muffier which can beeffectively used for a rnulticylinder internal combustion engine in sucha manner that the exhaust gases from each cylinder of the engine aretreated successively and continuously.

Other objects and features will become apparent from the followingdetailed description.

Figure 1 is a view in perspective of the inner portion of a mufiler ofthis invention.

Figure 2 is a longitudinal cross-sectional view of a muffler of thisinvention.

Figure 3 is a sectional view on line 3-3 of Figure 2.

Figure 4 is a sectional view on line 4-4 of Figure 2.

Figure 5 is a view in perspective of a partition used in a muffler ofthis invention.

Figure 6 is a view in perspective of another partition which can be usedin a muffler of this invention.

Figures 7 and 8 are views in perspective of pipes which can be used in amuffler of this invention.

Figure 9a is a View in perspective of the portion of an exhaust outletpipe, said portion being positioned within a muffler of this invention.

Figure 9b is a plan view of the pipe of Figure 9a.

Figure 10 is a sectional view on line l0-10 of Figure 2.

Figure ll is a sectional view on line 11-41 ure 2.

Figure 1211 is a partial longitudinal view of a second embodiment of aniuiller of this invention wherein the pipes of Figures 7 and 8 aresubstituted for pipes as shown in Figure 1.

Figure 1212 is a sectional Figure 12a.

More specifically, an outer cylindrically shaped casing 2 is providedwith a forward end wall 4 and a rear end wall 6, said end wall 4 havingpositioned therein an exhaust inlet pipe 3 and said end wall 6 havingpositioned therein an exhaust outlet pipe 10. In said exhaust inlet pipe8 are slots 12 which extend into pipe 8 for a portion of its length asshown in Figure 2.

Concentric-ally positioned within the outer casing 2 is a cylindricallyshaped inner casing 14, which is pr0- vided with a forward end wall 16and a rear end wall 18. Mounted within the casing 14 are transverselypositioned partitions 2t 22, and 2d, the distance between each beingapproximately equal, said partitions forming separate chambers 26, 28,3t), and 32, partition 22 being perforated as shown by the passagewaysor perforations 34 therethrough.

The chambers 26, 28, 3t), and 32 are interconnected by open-ended pipes36 and 37, passageways 34, and openended pipes 38 and 39, respectively.I

The end walls 16 and 4 define with the outer casing wall 44 an expansionchamber 42, and end walls 6 and 18 define with the outer casing wall anexpansion chamber 44. The exhaust gas inlet pipe 3 terminates in thechamber 42, and the exhaust gas outlet pipe It: extends through chamber44, partition 18, chamber 32, through partition 24, through chamber 30,through partition 22, having its opening 46 terminating both in chamber30 and in chamber 28, as shown in Figure 2. Positioned in partition 16are open-ended pipes 48 and 5d, the respective ends of each terminatingin chambers 42 and 26. The pipes 48 and Si) are preferably positioneddirectly above and directly below the pipe 8 and in such a manner thattheir respective longitudinal axes are on a horizontal plane to thehorizontal plane of the longitudinal axis of the pipe 8 and theirrespective vertical axes are on a vertical plane coinciding with thevertical plane of the of Figview on line 12b12l1 of vertical axis ofpipe 8, as shown. It is preferable that the pipes 48 and 50 and the pipe8 terminate on a plane parallel to the rear end wall 16, as shown inFigure 2.

The pipes 36 and 37 are positioned in partition in such a manner thattheir respective longitudinal axes are on a horizontal plane coincidingwith the horizontal plane of the longitudinal axis of the pipe 8 andtheir respective vertical axes are on a vertical plane parallel to thevertical plane of the vertical axis of pipe 8, the pipes 36 and 37 beingspaced from the pipe 8 preferably as shown. The pipes 36 and 37terminate in chambers 26 and 28, as shown, and preferably on a planecoinciding with the plane in chamber 26 on which the pipes 4-3 andterminate, said plane being parallel to the wall 16.

The open-ended pipes 54 and 55 are positioned in wall 18 in a mannersimilar to pipes 48 and 50 in wall 16 and in the same relationship topipe 10 as are pipes 43 and 50 to pipe 8, pipe 10 being so positionedthat its longitudinal axis is on a plane coinciding with thelongitudinal axis of pipe 8. The inner end of exhaust outlet pipe 10 ispreferably cut diagonally, thus allowing the opening 46 to terminateboth in chamber 28 and chamber 30.

In the annular space 56 formed by the inner peripheral surface of theWall 49 of easing 2 and the outer peripheral surface of the Wall 57 ofthe casing 14 are positioned the equally spaced circular partitions 58,59, 60, 61, 62, 63, 64, 65, and 66 extending laterally from the wall 57to the wall 40. Each of said partitions has an opening extending fromthe wall 57 to the wall 40, the opening in partition 58 being defined bythe edges 67 and 68 and the opening in partition 59 being defined by theedges 69 and 70. As shown in the drawings, the partitions 60-66,inclusive, are similar to partition 59 and the openings in saidpartitions are similar to the opening in partition 59. If desired, thepartitions 59-66, inclusive, may have a configuration similar topartition 58, as shown in Figure 6. To obtain the best results it isnecessary that the openings in each partition be confined within a 90segment of the partition and preferably subtend no more than one-twelfthof the outer circumference of the partition. The circumferentialdistance along the perimeter of the respective partition between thetopmost points on the respective edges of each opening will therefor beat least eleven-twelfths of the outer perimeter of said partition.ranged that the edges 67 and 70, 69 and 72, 71 and '74, and so on, areparallel, 69 and 70 being the edges of the opening in partition'59, 71and 72 being the edges of the opening in partition 60, 73 and 74 beingthe edges of the opening in partition 61. If the partitions are all ofthe configuration of partition 58, one edge of the opening in eachpartition will be parallel to and adjacent to edge 67, and the outeredge of the opening will be parallel to and adjacent to edge 68, and soon. It is preferable that the cross-sectional area of each opening beapproximately the same and that the partitions be so arranged that therespective openings be substantially directly adjacent one another, asshown in Figure 1. Edges 67, 69, 71, 73, '75, 77, 79, 81, and 83 are thetop edges of the respective openings, and edges 68, 70, 72, 74, 76, 78,80, S2, and 84 are the bottom edges of the respective openings. Edge 70is the edge in the opening of partition 59 opposite to the edge 67 inpartition 58, edge 72 is the edge in the opening of partition 60opposite to the edge 69 in partition 59, and so on. In Figure l, asshown, wherein partitions 60-66, inclusive, are of a configurationsimilar to partition 59, it is seen that the edges 67-84, inclusive, areall parallel to each other.

The partitions 58-66, inclusive, are preferably arranged that angularmembers or partitions 85-92, inclusive, will form an angle ofapproximately 30 with the respective partitions at the edges 67, 69, 71,73, 75, 77, 79, 81, and 83 of the respective openings therein. Theangular partition or member 85 is attached to partition 58 at edge 67thereof and to partition 59 at edge 7 0 thereof, the angular Thepartitions are so ari partition or member 86 is attached to partition 59at edge 69 thereof and to partition 60 at edge 72 thereof, and so onwith angular members 87-92, inclusive. Each of the angular partitions ormembers -92, inclusive, is thus positioned between, and in contact withat all points on its respective'upper and lower edges, the outerperipheral surface of the wall 57 of the inner casing 14 to the innerperipheral surface of the wall 40 of the outer casing 2.

Because of the aforesaid particular preferred arrangement andconfiguration of the partitions 58-66, inclusive, of the openings intheir respective partitions, and of the angular members 85-92,inclusive, the exhaust gases and sound waves will be conducted into theannular space 56 through the opening defined by edges 67 and 68 inpartition 58, along a substantially circular path in the space betweenthe partitions 58 and 59, along a substantially angular path along theangular member 85 after being deflected by said member 85, and then intothe space between partitions 59 and 60, and so on, and then through theopening defined by edges 83 and 84 in partition 66, in the direction ofthe arrows as shown in Figure 1. Because of said structural features,accumulation and storage of the expanded exhaust gases and unobstructedpassage for said gases having the sound waves traveling therethroughwill be prevented in the passage thereof from expansion chamber 42 tochamber 44.

For open-ended pipes 48, 50, 36, 37, 38, 39, 54, and 55, may besubstituted the open-ended 90 elbow pipes 93 and 94, as shown in Figures7 and 8, respectively. When such pipes are utilized, they are positionedas shown in Figure 12. The pipes substituted for 36 and 37 arepositioned as shown in Figure 12b.

The exhaust gases pass from the engine into the inlet pipe 8 and arecaused to flow therefrom into the chamber 42 wherein said gases expand.The exhaust gases so expanded are caused to divide into two streams,each stream having sound waves therethrough; one stream or portion iscaused to flow through the combined substantially circular and angularpath defined by the partitions 58-66, inclusive, the openings thereinand the angular members 85-92, inclusive, as hereinbefore described,into chamber 44 wherein a further expansion of said gases is broughtabout. In traveling through the path created by the structuralcomponents positioned in annular space 56, the gas is caused to flowthrough 360 between each partition before it is caused to flow into thesaid chamber 44, whereby said stream or portion of exhaust gas isconducted through pipes 54 and 55 into chamber 32 and then through pipes38 and 39 into chamber 30, the positions of said pipes 54, 55, 33 and 39in relation to each other causing said stream of gases to be conductedalong a tortuous or zig-zag path within chamber 32 and along asubstantially straight-line path in chamber 30. By conducting saidstream or portion of exhaust gases through the aforedescribedcombination of paths, the well known explosive-impulse noise factorcaused by the pressure, in said exhaust gases, of the successiveconcentrations at relatively high pressures and intermediateconcentrations at relatively low pressures is reduced as a result of theexpansion of said gases and as a result of bathing action. Thus, thecharacteristic sound of the successive explosions is greatly attenuated.

The other stream or portion of exhaust gases is caused to flow through atortuous or zig-zig path in the pipes 48 and 50, in the chamber 26, andthrough a substantially straight-line path in the chamber 28. Thus, thepressure impulses of that portion of the exhaust gases are caused tolevel out and the characteristic sound of the successive explosions arefurther attenuated.

The distance through which the first described stream of exhaust gaseshaving the sound waves traveling therethrough, viz. that portion passingfrom chamber 42 through annular space 56, through chamber 44, throughchamber 32, and through chamber 30, passes is one half wave length, or amultiple thereof, depending upon the degree of attenuation desired,greater than the wave length of said sound waves, and thus the firstdescribed stream or portion of exhaust gases will lag behind the seconddescribed stream or portion of the gases by a dis tance approximatelyequal to one half wave length, or a multiple thereof, of said soundwaves. The wave length may be easily calculated having available theengine speed, number of cylinders in said engine, and the velocity ofsound in a hot gas.

Thus, the two streams or portions of the exhaust gases meet in thevicinity of the perforated partition, said two streams through which thesound waves are traveling, viz. said exhaust gases are a carrying mediumfor the the sound waves from the engine, being out of phase by one-halfthe wave length of said sound Waves, and the sound waves approachingfrom opposite directions are canceled by interference. Because of theopening, which is cut diagonally, of pipe being so positioned, as shownin Figure 2, a greater volume is provided wherein the exhaust gases uponmeeting, after approaching from opposite directions, can be easily andquickly removed, thereby preventing accumulation and storage in thatmuffier portion.

The muflier is so constructed that the volume of chamber 42 is at leastapproximately ten times the displacement volume of one cylinder thusmaking it capable of use for both single cylinder and multicylinderengines, since thereby the exhaust gases from each cylinder are treatedsuccessively and continuously. This feature in combination with theother structure features herein described bring about excellentsilencing effects.

From the drawings it may be seen that the cylindrical wall of exhaustpipe has therein two oppositely positioned slots 12 in the lower portionthereof leading from the inner portion of the outlet pipe to chambers 28and 30. Also, it is seen that said slots extend longitudinally from theopening of said outlet pipe and terminate in that portion of the pipe 10which is in chamber 36. To obtain the desired results, said slots mustterminate in that portion of pipe 10 positioned in chamber 30. By theinclusion of said slots in pipe 10, there will be a diminishing of anyresidual noise before the so treated exhaust gas enters the atmopshere.

By utilizing the structural features shown in Figures 12a and 12bexcellent silencing effects are also attained.

Further, sound absorbent lining may be used in either casing or in bothcasings.

The approximate dimensions of one mufiier contemplated herein are asfollows:

Many alterations and changes may be made without departing from thespirit and scope of this invention which is set forth in the appendedclaims which are to be construed as broadly as possible in view of theprior art.

I claim:

1. A muffler comprising an outer cylindrically shaped casing having endwalls, a concentrically positioned cylindrically shaped inner casingwithin said outer casing, said inner casing having end walls spaced fromthe respective end walls of said outer casing, the outer peripheralsurface of said inner casing being spaced from and defining an annularspace with the inner peripheral surface of said outer casing, an exhaustgas inlet pipe at one end of said outer casing, an exhaust gas outletpipe at the other end of said outer casing, means for conducting a firstportion of the exhaust gases from the inlet pipe to the outlet pipethrough a combined substantially circular and substantially angular pathin said annular space, through a tortuous path in said inner casing, andthen through a substantially straight-line path in said inner casing,and means for conducting the remaining portion of the exhaust gases fromthe inlet pipe to the outlet pipe through a tortuous path in said innercasing and then through a substantially straight-line path in said innercasing in a direction opposite to the direction of the first portion ofthe exhaust gases passing through the tortuous and then substantiallystraight-line path.

2. A mufiler comprising an outer cylindrically shaped casing having endwalls, a concentrically positioned cylindrically shaped inner casingwithin said outer casing, said inner casing having end walls spaced fromthe respective end walls of said outer casing, the outer peripheralsurface of said inner casing being spaced from and defining an annularspace with the inner peripheral surface of said outer casing, an exhaustgas inlet pipe at one end of said outer casing, an exhaust gas outletpipe at the other end of said outer casing, means for conducting a firstportion of the exhaust gases from the inlet pipe to the outlet pipethrough a substantially circular path in said annular space, through atortuous path in said inner casing, and then through a substantiallystraight-line path in said inner casing, and means for conducting theremaining portion of the exhaust gases from the inlet pipe to the outletpipe through a tortuous path in said inner casing and then through asubstantially straight-line path in said inner casing in a directionopposite to the direction of the first portion of the exhaust gasespassing through the tortuous and then substantially straight-line path.

3. A mufller comprising an outer cylindrically shaped casing having endwalls, a concentrically positioned cylindrically shaped inner casingwithin said outer casing, said inner casing having end walls spaced fromthe respective end walls of said outer casing, the outer peripheralsurface of said inner casing being spaced from and defining an annularspace with the inner peripheral surface of said outer casing, an exhaustgas inlet pipe at one end of said outer casing, an exhaust gas outletpipe extending from within said inner casing to the other end of saidouter casing, means for conducting a first portion of the exhaust gasesfrom the inlet pipe through a combined substantially circular andsubstantially angular path in said space, through a tortuous path insaid inner casing, and then through a substantially straight-line pathin said inner casing to the exhaust gas outlet pipe Within said innercasing, and means for conducting the remaining portion of the exhaustgases from the inlet pipe through a tortuous path in said inner casingand then through a substantially straightline path in said inner casingto the exhaust gas outlet pipe within said inner casing in a directionopposite to the direction of the first portion of the exhaust gasespassing through the tortuous and then substantially straight-line path.

4. A muffler comprising an outer cylindrically shaped casing having aforward end wall and a rear end wall, a concentrically positionedcylindrically shaped inner casing within said outer casing, said innercasing having a forward end wall and a rear end wall, said forward endwall of said inner casing and said forward end wall of said outer casingdefining an expansion chamber, the outer peripheral surface of saidinner casing being spaced from and defining an annular space with theinner peripheral surface of said outer casing, an exhaust gas inlet pipeterminating in said expansion chamber, an exhaust gas outlet pipe at theother end of said outer casing, means for conducting a first portion ofthe exhaust gases from the expansion chamber to the outlet pipe througha combined substantially circular and substantially angular path in saidannular space, through a tortuous path in said inner casing, and thenthrough a substantially straight-line path in said inner casing, andmeans for conducting the remaining portion of the exhaust gases from theexpansion chamber to the outlet pipe through a tortuous path in saidinner casing and then through a substantially straight-line path in saidinner casing in a direction op- 7 posite to the direction of the firstportion of the exhaust gases passing through the tortuous and thensubstantially straight-line path.

5. A mufiler comprising an outer cylindrically shaped casing having aforward end wall and a rear end Wall, a concentrically positionedcylindrically shaped inner casing within said outer casing, said innercasing having a forward end wall spaced from the forward end wall ofsaid outer casing and a rear end wall spaced from the rear end Wall ofsaid outer casing, the outer peripheral surface of said inner casingbeing spaced from and defining an annular space with the innerperipheral surface of said outer casing, an exhaust gas inlet pipe atthe forward end of said outer casing, an exhaust gas outlet pipe at therear end of said outer casing, means for conduct ing a first portion ofthe exhaust gases from the inlet pipe tothe outlet pipe through acombined substantially circular and substantially angular path in saidannular space, through a tortuous path in said inner casing, and thenthrough a substantially straight-line path in said inner casing, saidmeans including a first expansion chamber defined by the forward endwall of said outer casing and the forward end wall of said inner casingand a second expansion chamber defined by the rear end wall of the outercasing and the rear end wall of the inner casing, and means forconducting the remaining portion of the exhaust gases from the inletpipe to the outlet pipe through a tortuous path in said inner casing andthen through a substantially straight-line path in said inner casing ina direction opposite to the direction of the first u portion of theexhaust gases passing through the tortuous and then substantiallystraight-line path, said means ineluding said first expansion chamber.

6. A mufiler comprising an outer cylindrically shaped v lindricallyshaped inner casing within said outer casing, said inner casing havingend walls spaced from the respective end Walls of said outer casing, theouter peripheral surface of said inner casing being spaced from anddefining an annular space with the inner peripheral surface of saidouter casing, an exhaust gas inlet pipe at one end of said outer casing,an exhaust gas outlet pipe at the other end of said outer casing, meansfor conducting a first portion of the exhaust gases from the inlet pipeto the outlet pipe through a combined substantially circular andsubstantially angular path in said annular space, through a tortuouspath in said inner casing, and then through a substantiallystraight-line path in said inner casing, said means including in saidannular space a t plurality of substantially equidistant transverselypositioned partitions, each of said partitions extending from the outerperipheral surface of said inner casing, at all points thereof, to theinner peripheral surface of said outer casing, at all points thereof,each of said parti- Cir pipe through a tortuous path in said innercasing and then through a substantially straight-line path in said innercasing in a direction opposite to the direction of the first portion ofthe exhaust gases passing through the tortuous and then substantiallystraight-line path.

7, A muffler comprising an outer cylindrically shaped casing, saidcasing having a dome shaped forward end wall and a dome shaped rear endWall, a concentrically positioned inner cylindrically shaped casinghaving forward and rear end walls, said forward end Wall of said outercasing and said forward end wall of said inner casing defining a firstexpansion chamber, said rear end wall of said outer casing and said rearend Wall of said inner easing defining a second expansion chamber, theouter peripheral surface of said inner casing being spaced from anddefining an annular space with the inner peripheral surface of saidouter casing, a plurality of substantially equidistant transverselypositioned partitions in said annular space, each of said partitionsextending from the outer peripheral surface of said inner casing at allpoints thereof to the inner peripheral surface of said outer casing atall points thereof, each of said partitions having an opening extendingfrom the outer peripheral surface of said inner casing to the innerperipheral surface of said outer casing, each of said partitions havingan opening extending from the outer peripheral surface of said innercasing to the inner peripheral surface of said outer casing, saidopenings being in like portions of said partitions, a plurality ofangularly positioned Walls, each of said walls extending from one edgeof an opening at all points thereof to the opposite edge of the openingin the adjacent partition at all points thereof, an exhaust gas inletpipe terminating in said first expansion chamber, a transverselypositioned partition in said inner casing spaced from and defining aninner first chamber with said forward end wall of said inner casing, aplurality of open-ended pipes positioned in said forward end wall ofsaid inner casing in offset relationship with said exhaust gas inletpipe, each of said pipes having one end terminating in said firstexpansion chamber and the other end terminating in said first chamber, aperforated transversely positioned partition in said inner casing spacedfrom and defining with said latter partition an inner second chamber, aplurality of open-ended pipes positioned in said latter partition, eachbeing positioned in offset relationship with each of said latterplurality of pipes and having one end terminating in said inner firstchamber and the other end terminating in said second chamber, atransversely positioned partition in said inner easing spaced from saidperforated partition and said rear end wall of said inner casing anddefining an inner third chamber with said perforated partition and aninner fourth chamber with said rear end wall, an exhaust gas outlet pipeextending through said second expansion chamber and having one endterminating in both said inner second and thirdchambers, a plurality ofopen-ended pipes in said rear end wall of said inner casing, each ofsaid pipes having one end terminating in said second expansion chamberand the other end terminating in said inner fourth chamber, a pluralityof open-ended pipes positioned in said partition spaced from saidperforated partition and said rear end wall of said inner casing, eachbeing positioned in offset relationship with each of said latterplurality of pipes and having one end terminating in said inner fourthchamber and the other end terminating in said third chamber.

No references cited.

